Heating and cooling the space in residential and commercial buildings accounts for a primary share of building energy consumption. Existing buildings use either an air conditioning system or a whole house fan for cooling and ventilating residential and commercial building structures. Traditional air conditioning systems function by altering the temperature and humidity of the air and then pump the treated air throughout the structure. The thermostat powers on the air conditioner until the structure reaches a set point temperature. While effective at conditioning the air, such traditional air conditioning systems are costly to run and not energy efficient. Additionally, when the outside ambient air temperature is lower than the internal air temperature, outside ambient air could instead be used to effectively cool the structure, reducing the need to run a costly air conditioning system. Further, air conditioning systems merely circulate air located within a building, and do not bring any outside air, so any harmful environmental elements (e.g. dust, disease, chemicals) remain within the building.
In response to such problems, some structures instead use whole house fans to force air through the structure. Whole house fans consist of one or more exhaust fans, typically placed in the attic or an upper floor, and function by creating a negative pressure inside of the structure to draw cooler air in from the outside. The cooler outside air is forced up through the ceiling into the attic where the air is exhausted out through a vent. Louvered shutters are often placed over the vent to prevent cooled or heated air from escaping when the fan is not in use. Whole house systems move large amounts of air and allow for the entire structure air volume to be recycled with multiple air exchanges per hour, removing latent heat within the structure. Traditional whole house fans are installed on the attic floor such that they directly contact the ceiling of the structure. As such, the large capacity whole house fans, necessary to create sufficient negative pressure to draw the cooler air inside in the structure, can create undesirable noise and vibrations that penetrate the occupied space of the building. Advantageously, these systems require less energy than air conditioning systems and can reduce the need for air conditioning and therefore reduce structure energy consumption while still providing a comfortable space. However, such whole house fans require open windows to serve as intake air vents. Thus, the user is required to manually control the air flow. The opened windows, however, can allow in dust, pollen and other pollutants from the exterior incoming air. Additionally, the cooling capabilities of whole house fans are limited by the ambient outside air. Whole house fans are incapable of lowering the temperature and humidity of the air drawn into the building. Accordingly, whole house fans are not effective at cooling the space when the outside ambient air temperature is higher than the internal air temperature. Thus, a user operating the whole house fan under unsuitable conditions may actually heat the space when they intended to use the fan to cool the space.